Such systems are well known and the invention more particularly relates to cordless telephony devices known by the name of CT0, CT1, . . . , CTx.
One of the problems posed with this type of system is due to the necessity of periodically verifying whether the handset and the base station are validly interconnected. For this purpose, an identification code is transmitted in a signal frame. This transmission of a frame is superposed on the call signals which is highly annoying to the listeners. There is also proposed to reduce the perception of call signals during the transmission of these signal frames. However, as a result of the drift of the circuits, it is not always possible to ensure the simultaneity of the reception of the frames with the cutting off of the call signals and this calls forth an annoying effect for the user, because these frames carry unpleasant noise when listening.